The present invention relates generally to electrically powered apparatus, and more particularly to a novel electric motor having an oscillatory direct output and being ideally suited for use on automotive vehicles, and to several novel vacuum pumps and fuel pumps especially adapted to be driven thereby.
The electric motor of the present invention provides a number of advantages over the known prior art, including: use of Applicant's discovery of a force reversal phenomenon which provides automatic cycling without requiring external timing mechanisms or complex delay devices, whereby the motor can be operated as a highly energy efficient demand device with a full power stroke on each cycle and minimum power consumption for mere switching; operation on low voltage D.C. power, so that it is ideally suited for automotive applications; simplicity in design and ease of manufacture with no critical tolerances; high output for size, weight and power consumption, thus ideal for automotive uses; minimum current drain in certain exemplary embodiments having double contacts and coils; and the use of a unique rubber and iron cushioning material to reduce noise without a proportional loss in efficiency.
The exemplary vacuum pumps of the present invention are especially adapted to be powered by the aforesaid motor and therefore provide all of the aforesaid advantages. These are particularly significant in automotive vehicle applications in which the prime mover is a diesel engine or a stratified charge engine because these type engines generally have insufficient vacuum to operate normal vacuum-driven accessories. in addition, the pumps themselves are adapted for automatic cycling on demand, are simple in design and easy to manufacture with no critical tolerances, and have superior output for their size, weight and power consumption. One piston pump embodiment also incorporates a novel dash pot arrangement providing an air cushion to dampen piston impact.
The exemplary automotive vehicle fuel pumps of the present invention also operate as demand devices and are especially adapted to be powered by the aforesaid motor. They therefore also provide all of the advantages thereof. In addition, because they operate on demand, they need not be mounted in the fuel tank to provide easy bypass of excess fuel, and they consume less energy than conventional electrical and mechanical diaphragm fuel pumps. Furthermore, one fuel pump embodiment of this invention is capable of modulating its output in response to engine load so that maximum fuel output occurs at full throttle and minimum fuel output at idle, with modulation in-between these conditions. Reduced output at idle results in reduced fuel pressure, and in carbureted engines this means less fuel consumption. Another embodiment modulates fuel output in response to engine load and speed, giving even greater control over fuel delivery. This latter embodiment responds to engine speed in a unique manner by sensing the pressure differential across the coolant pump, and then compensating for any nonlinearity. The fuel pumps of this invention also are simple in design and easy to manufacture with no critical tolerances, and have superior output for their size, weight and power consumption.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.